In a conventional mobile communication system, services for personal mobile communication device occupy most of data traffic. Since required data rate & quality of service (QoS) are inverse proportional to mobility of the mobile device, current communication system offers services with good quality for a mobile device with low mobility and offers services with stability without link failures for a mobile device with high mobility.
As frequency of use of wireless communication and criteria of usage of wireless communication increase, needs of providing high data rate & high QoS for a user with high mobility increase. For example, a plurality of users in a public transportation may want to watch multimedia contents while the transportation, or a plurality of passengers in personal vehicle which is driving in a highway may use different wireless communication services. In the above-mentioned cases, mobile communication system should be able to provide wireless services with good quality for the users with high mobility.
It is a new model which is not present in current wireless communication model. To support this, mobile communication network needs to be enhanced to a level of revolution or a new system to implement the new model without any influence to current network infrastructures should be configured.
There is a discussion about V2X (Vehicle to Infra/Vehicle/Nomadic) communication technic to support efficient communication for users in vehicles. V2X includes a communication between vehicle to infrastructure (V2I) and a communication between vehicle to vehicle (V2V).
When a large size of an antenna array is installed outside vehicle and is operated to provide high quality service to a high speed moving vehicle, aesthetic problems and aerodynamic problems can be raised. Thus, a study of an antenna array for vehicles is needed.